The low-power nucleus of PKS 1246 - 410 in the Centaurus cluster

Abstract

We present Chandra, Very Large Array (VLA) and Very Long Baseline Array (VLBA) observations of the nucleus of NGC 4696, a giant elliptical in the Centaurus cluster of galaxies. Like M87 in the Virgo cluster, PKS 1246-410 in the Centaurus cluster is a nearby example of a radio galaxy in a dense cluster environment. In analysing the new X-ray data, we have found a compact X-ray feature coincident with the optical and radio core. While nuclear emission from the X-ray source is expected, its luminosity is low, < 1040 erg s-1. We estimate the Bondi accretion radius to be 30 pc and the accretion rate to be 0.01 M⊙ yr-1, which under the canonical radiative efficiency of 10 per cent would overproduce by 3.5 orders of magnitude the radiative luminosity. Much of this energy can be directed into the kinetic energy of the jet, which over time inflates the observed cavities seen in the thermal gas. The VLBA observations reveal a weak nucleus and a broad, one-sided jet extending over 25 pc in position angle -150°. This jet is deflected on the kiloparsec-scale to a more east-west orientation (position angle of-80°). © 2005 RAS.